U.S. patent number 5,865,319 [Application Number 08/671,331] was granted by the patent office on 1999-02-02 for automatic test handler system for ic tester.
This patent grant is currently assigned to Advantest Corp.. Invention is credited to Hisao Hayama, Katsumi Kojima, Shin Nemoto, Hiroshi Okuda.
United States Patent |
5,865,319 |
Okuda , et al. |
February 2, 1999 |
Automatic test handler system for IC tester
Abstract
An automatic test handler system for automatically supplying IC
devices to be tested to an IC tester and sorting the tested IC
devices based on the test results. The system includes a testing
machine for testing the IC devices by contacting the IC devices
with test contactors. Test signals are provided from the IC tester
and the resulting signals from the IC devices are received. The
testing machine is installed in a test room in which dust,
temperature and humidity are controlled in a high degree. A sorting
machine is installed outside of the test room for sorting the IC
devices that have been tested based on the test results. The
sorting machine has a plurality of sort stations for receiving the
IC devices based on categories defined in the test results. Tray
cassettes hold a plurality of IC trays containing the IC devices,
and both the tray cassettes and IC trays are provided with
identification numbers. The trays are horizontally transferred on
the testing machine and the sorting machine, and a data
communication network connected between the testing machine and the
sorting machine transmits the test results and position information
of the IC devices in the IC trays.
Inventors: |
Okuda; Hiroshi (Tatebayashi,
JP), Nemoto; Shin (Yono, JP), Hayama;
Hisao (Gyoda, JP), Kojima; Katsumi (Hasuda,
JP) |
Assignee: |
Advantest Corp. (Tokyo,
JP)
|
Family
ID: |
13442783 |
Appl.
No.: |
08/671,331 |
Filed: |
June 27, 1996 |
Foreign Application Priority Data
|
|
|
|
|
Dec 28, 1994 [JP] |
|
|
7-70826 |
|
Current U.S.
Class: |
209/574; 209/571;
209/573 |
Current CPC
Class: |
G01R
31/2851 (20130101); G01R 31/01 (20130101); G01R
31/2893 (20130101) |
Current International
Class: |
G01R
31/01 (20060101); G01R 31/28 (20060101); B07C
005/344 () |
Field of
Search: |
;209/552,571,573,574 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Terrell; William E.
Assistant Examiner: Deuble; Mark
Attorney, Agent or Firm: Muramatsu & Associates
Claims
What is claimed is:
1. An automatic test handler system for handling IC devices for
testing the IC devices by an IC tester and sorting the tested IC
devices based on the test results, comprising:
a testing machine for testing said IC devices by contacting said IC
devices with test contactors whereby providing test signals from
said IC tester and receiving resulted signals from said IC devices,
said testing machine being installed in a clean room environment
wherein dust, temperature and humidity are controlled in a high
degree, said testing machine having a loader for loading a
plurality of IC trays each of which carries a plurality of IC
devices to be tested, a test area having said test contactors, an
unloader for receiving IC devices that have been tested on an empty
IC tray, and a test controller for controlling an overall operation
of said testing machine;
a sorting machine installed outside of said clean room environment
for sorting said IC devices that have been tested based on said
test results, said sorting machine having a loader for loading a
plurality of said IC trays transferred from said unloader of said
testing machine, a plurality of sorting stations for receiving said
IC devices based on categories defined in said test results and a
sort controller for controlling an overall operation of said
sorting machine;
a tray cassette for installing said plurality of IC trays
containing said IC devices to be tested and loading said IC trays
in said loader of said testing machine and for receiving said IC
trays carrying said IC devices that have been tested at said
unloader of said testing machine, said tray cassette being
transferred to said loader of said sorting machine prior to sorting
said IC devices, said tray cassette being provided with a tray
cassette identification number;
each of said IC tray is provided with an IC tray identification
number, said IC trays being horizontally transferred on said
testing machine and said sorting machine; and
a data communication network connected between said testing machine
and said sorting machine for transmitting said test results and
position information of said IC devices in said IC trays and said
identification numbers, wherein said data communication network
transmits said test results and said position information and said
identification numbers from said test controller in said testing
machine to said sort controller in said sorting machine.
2. An automatic test handler system as defined in claim 1, wherein
said sorting machine reads said tray cassette identification number
when said tray cassette having tested IC devices is loaded in said
loader of said sorting machine, said sorting machine confirming
said tray cassette identification number with said identification
numbers received through said data communication network.
3. An automatic test handler system as defined in claim 1, wherein
said sorting machine reads said IC tray identification number of an
IC tray in an uppermost position of said tray cassette when said
tray cassette is loaded in said loader of said sorting machine,
said sorting machine confirming said IC tray identification number
with said identification numbers received through said data
communication network.
4. An automatic test handler system as defined in claim 1, wherein
said IC tray is emptied in said loader of said testing machine and
transferred to said unloader of said testing machine to receive
said IC devices that have been tested.
5. An automatic test handler system as defined in claim 1, wherein
said testing machine includes a movable arm and a movable carrier
to pick and place said IC devices within an area defined by said
movable arm and said movable carrier.
6. An automatic test handler system as defined in claim 1, wherein
said test contactors in said testing machine are connected to a
test head of said IC tester to provide said test signals from said
IC tester to said IC devices and to transmit said resulted signals
from said IC devices to said IC tester.
7. An automatic test handler system as defined in claim 1, wherein
said sorting machine includes a movable arm and a movable carrier
to pick and place said IC devices within an area defined by said
movable arm and said movable carrier.
8. An automatic test handler system as defined in claim 1, wherein
said identification numbers of said tray cassette and said IC tray
are bar codes to be read by a bar code reader.
9. An automatic test handler system for handling IC devices for
testing the IC devices by an IC tester and sorting the tested IC
devices based on the test results, comprising:
a testing machine for testing said IC devices by contacting said IC
devices with test contactors whereby providing test signals from
said IC tester and receiving resulted signals from said IC devices,
said testing machine being installed in a clean room environment
wherein dust, temperature and humidity are controlled in a high
degree, said testing machine having a loader for loading a
plurality of IC trays each of which carries a plurality of IC
devices to be tested, a test area having said test contactors, an
unloader for receiving IC devices that have been tested on an empty
IC tray, and a test controller for controlling an overall operation
of said testing machine and for providing test results of said IC
devices to a host computer;
a sorting machine installed outside of said clean room environment
for sorting said IC devices that have been tested based on said
test results, said sorting machine having a loader for loading a
plurality of said IC trays transferred from said unloader of said
testing machine, a plurality of sorting stations for receiving said
IC devices based on categories defined in said test results and a
sort controller for controlling an overall operation of said
sorting machine and for receiving said test results from said host
computer;
a tray cassette for installing said plurality of IC trays
containing said IC devices to be tested and loading said IC trays
in said loader of said testing machine and for receiving said IC
trays carrying said IC devices that have been tested at said
unloader of said testing machine, said tray cassette being
transferred to said loader of said sorting machine prior to sorting
said IC devices, said tray cassette being provided with a tray
cassette identification number;
each of said IC tray is provided with an IC tray identification
number, said IC trays being horizontally transferred on said
testing machine and said sorting machine; and
a data communication network connected between said testing machine
and said sorting machine for exchanging data regarding said test
results, position information of said IC devices in said IC trays
and said identification numbers, said host computer controlling
said exchanging data between said testing machine and said sorting
machine, wherein said data communication network sends said test
results and said position information and said identification
numbers from said test controller in said testing machine to said
sort controller in said sorting machine through said host
computer.
10. An automatic test handler system as defined in claim 9, wherein
said sorting machine reads said tray cassette identification number
when said tray cassette having tested IC devices is loaded in said
loader of said sorting machine, said sorting machine confirming
said tray cassette identification number with said identification
numbers received through said data communication network.
11. An automatic test handler system as defined in claim 9, wherein
said sorting machine reads said IC tray identification number of an
IC tray in an uppermost position of said tray cassette when said
tray cassette is loaded in said loader of said sorting machine,
said sorting machine confirming said IC tray identification number
with said identification numbers received through said data
communication network.
12. An automatic test handler system for efficiently handling,
testing, and sorting IC devices in the minimum amount of clean room
space, comprising:
a plurality of trays each of which is adapted to hold a plurality
of the IC devices;
a plurality of cassettes each of which is adapted to hold a
plurality of the trays;
a testing machine installed in a clean room for testing the IC
devices, the testing machine having a test area including a
plurality of test contractors adapted to electrically connect with
and test said IC devices, the testing machine further including a
loader for loading said trays into proximity with the test area,
and an unloader for receiving IC devices that have been tested and
placing them in trays, the trays being positioned in cassettes;
a sorting machine installed outside of a clean room environment for
sorting the IC devices that have been tested based on the test
results;
a carrier for transferring the cassettes containing the trays
having IC devices that have been tested from the unloader to the
sorting machine;
a means for externally identifying each cassette and each tray;
and
a controller for controlling an overall operation of the testing
machine, loader, unloader, and sorting machine, the controller
being supplied with information from the testing machine with
regard to the test results of each IC device within each tray, the
system further including at least one device for recognizing the
means for externally identifying each cassette and each tray and
communicating with the controller, the controller therefore
monitoring the position of each tray and cassette, and
communicating the test results of each IC device to the sorting
machine via a data communication network.
13. An automatic test handler system as defined in claim 12,
wherein the means for externally identifying each cassette and each
tray comprises tray identification numbers and cassette
identification numbers.
14. An automatic test handler system as defined in claim 13,
wherein the device for recognizing the means for externally
identifying each cassette and each tray comprises a bar reader.
15. An automatic test handler system as defined in claim 13,
wherein said sorting machine includes a loader and reads said tray
cassette identification number when said tray cassette having
tested IC devices is loaded therein, said sorting machine
confirming said tray cassette identification number with said
identification numbers received through said data communication
network.
16. An automatic test handler system as defined in claim 12,
wherein said IC tray is emptied in said loader of said testing
machine and transferred to said unloader of said testing machine to
receive said IC devices that have been tested.
17. An automatic test handler system as defined in claim 12,
wherein said carrier is a belt conveyor.
18. A method of testing IC devices, comprising:
placing a plurality of IC devices to be tested in a plurality of
trays, each having a means for tray identification thereon;
placing a plurality of the trays with IC devices on a plurality of
cassettes, each cassette having a means for cassette identification
thereon;
transporting said cassettes with trays to a loader of a test
machine, the test machine being installed in a clean room
environment;
removing the IC devices individually from individual trays and
transporting them into a test head of the test machine, and
bringing test contactors into electrical engagement with each IC
device;
testing each IC device with the test head;
communicating the test results for each IC device to a
controller;
replacing the tested IC devices on the trays and the trays on the
cassettes;
recording the location of each tested device with respect to the
tray and cassette with which it is associated;
monitoring the position of each of the trays and each of the
cassettes using the means for tray identification and the means for
cassette identification, respectively;
transporting cassettes containing trays of tested IC devices
outside of the clean room environment to a sorting machine while
continuing the step of testing IC devices;
communicating to the sorting machine the information regarding the
position of each of the trays and each of the cassettes and the
location of each tested device with respect to the tray and
cassette with which it is associated; and
sorting the tested IC devices with the sorting machine based on
their test responses.
19. The method of claim 18, wherein the step of monitoring
comprises externally reading the means for tray identification and
the means for cassette identification.
20. The method of claim 19, wherein the means for tray
identification and the means for cassette identification comprise
bar codes, and the step of reading is carried out with a bar code
reader.
21. The method of claim 18, wherein the step of transporting
cassettes containing trays of tested IC devices outside of the
clean room environment to a sorting machine is accomplished with a
conveyor.
22. The method of claim 18, wherein the steps of removing and
replacing are accomplished using pick and place arms.
23. The method of claim 18, wherein the step of sorting is
accomplished using pick and place arms.
Description
FIELD OF THE INVENTION
This invention relates to an automatic test handler for an IC
tester for automatically supplying IC devices to be tested to a
test position of the IC tester and sorting the tested IC devices
based on the test results, and more particularly, to an automatic
test handler system in which a sorting machine is mechanically
separated from a testing machine which is installed in a test room
and the sorting machine and the testing machine are electrically
connected by a data communication network.
BACKGROUND OF THE INVENTION
In testing IC devices, an automatic test handler is frequently used
in combination with an IC tester to automatically provide IC
devices (DUT) to be tested to a test position at a test head of the
IC tester. There are generally two types of test handlers, a
vertical transfer type handler wherein the IC devices to be tested
are transferred in a vertical direction with their own gravities
and a horizontal transfer type handler wherein IC devices placed on
a tray or carrier module are transferred in a horizontal direction
to the test position.
In a typical horizontal transfer type test handler, IC devices to
be tested are aligned on a tray in a loading area and picked, one
by one, and transferred to a test head of an IC tester and placed
on a test socket or contactor of the test head by a pick and place
mechanism or a movable arm of the test handler. The tested IC
devices are taken out from the test head and transferred to an
unloading area. The tested IC devices are classified to two or more
trays in a sorting area based on the test results.
Such a horizontal transfer type test handler is described in detail
in a Japanese patent application No. 5-275570 filed by the same
assignee of the present invention. FIG. 5 is a plan view showing
the configuration of the conventional test handler disclosed in the
Japanese patent application No. 5-275570.
In FIG. 5, a test handler 9 includes a movable arm 12 which is
movably mounted on a pair of rails 11.sub.1 and 11.sub.2. The
movable arm 12 moves on the rails 11.sub.1 and 11.sub.2 in a X
direction on the surface of the test handler 9. On the movable arm
12, there is provided a movable carrier 13 which moves along the
movable arm 12 in a Y direction on the surface of the test handler
9. Thus, the movable carrier 13 can take any positions on the
surface, i.e., the X-Y plane of the test handler 9 within the area
determined by the rails 11.sub.1 and 11.sub.2 and the movable arm
12.
In the movable area of the carrier 13, a loader 14, an unloader 23,
and an empty tray area 26 are provided as well as a heater area 15.
Sorters 24 and 25 are also provided in the movable area of the
movable carrier 13. More sorters may be provided depending on the
numbers of classification of the tested DUTs. In the right hand
side of FIG. 5, within the movable area of the carrier 13, the test
handler 9 includes buffers 16 and 22.
Another set of a movable arm and a movable carrier is used in a
test area 33 of the test handler 9. A movable arm 18 is movably
mounted on a pair of rails 17.sub.1 and 17.sub.2. The movable arm
18 moves on the rails 17.sub.1 and 17.sub.2 in a X direction on the
surface of the teat handler 9. On the movable arm 18, there is
provided a movable carrier 19 which moves along the movable arm 18
in a Y direction on the surface of the test handler 9. Thus, the
movable carrier 19 can take any positions on the surface, i.e., the
X-Y plane of the test handler 9 within the area determined by the
rails 17.sub.1 and 17.sub.2 and the movable arm 12. A test
contactor 21 is provided in the test area of the handler 9 which is
connected to the IC tester.
In the loader 14, a plurality of trays 7 are piled in a tray
cassette (not shown). Each of the trays 7 carries a plurality of
DUTs 10 aligned thereon. The DUTs in the uppermost tray are taken
out, one by one, or two or more at the same time, by the movable
carrier 13. The DUTs are placed on the heater area 15, if
necessary, to receive the heat for raising the inner temperature to
a predetermined level. This heating process is commonly used in an
automatic test handler to proceed a high temperature test for DUTs.
A test handler may also include a cooler to perform a low
temperature test.
The heated DUTs are then placed on the buffer 16 which moves in the
X direction to the dotted line position in FIG. 5 in the test area
33. In the test area 33, the movable carrier 19 picks the DUT 10 on
the buffer 16 and places the DUT on the test contactor 21. Although
not shown, test signals from the IC tester are provided to the test
contactor 21 and applied to the DUT 10. The resulting output
signals from the DUT 10 are transmitted to the IC tester through
the test contactor 21 to be evaluated by the IC tester by comparing
them with expected data.
After the test, the DUT 10 is picked by the movable carrier 19 and
placed on the buffer 22 which is positioned in the test area 33 as
shown in the dotted line of FIG. 5. The buffer 22 returns to the
original position where the movable carrier 13 is transferred to
the unloader 23. In this example, when the DUT is non-defective, it
is placed on the unloader 23, but if the DUT is defective, it is
placed on the sorter 24 or 25 depending on the type of defects. The
emptied trays in the loader 14 are shifted to the empty tray area
26.
As in the foregoing, the conventional automatic test handler 9 of
FIG. 5 handles the DUTs 10 and transfers the DUTs to the test head
of the IC tester to test various electric performances of the DUTs
under the predetermined environmental conditions such as the high
or low temperature. The DUTs are classified based on the test
results, such as (1) conforming devices (2) defective devices or
(3) devices need retest. If necessary, the defective devices are
further classified depending on the causes of the defects.
FIG. 6 is a schematic diagram showing a perspective view of the
automatic test handler of FIG. 5 in which the parts corresponding
to FIG. 5 are denoted by the same reference numerals. With
reference to FIG. 6, the outer configuration of the automatic test
handler for the IC tester is explained. Numeral 31 designates a
loader and unloader. When opening the cover by a handle 36, there
is shown the loader and unloader 31 wherein tray cassettes are
respectively provided. A plurality of IC trays 7, for example more
than twenty IC trays, are installed in each tray cassette. Each of
the IC tray 7 carries, for example 50 or more DUTs, depending on
the size of the DUT. Since the loader 14 has a capacity of 20-50 IC
trays, 1000-3000 DUTs are installed in the loader 14 prior to the
start of the test. As noted above, the DUTs are transferred
horizontally over the surface of the test handler.
The heater 15 is used for testing the DUTs under the high
temperature. Numeral 33 designates the test area where the DUTs are
placed on the test contactor. Although not shown, the test head of
the IC tester is fixed to the opening provided under the test area
33. The test head of the IC tester and the test contactor in the
test area 33 of the handler are electrically connected so that the
DUT is provided with the test signals from the IC tester when
placed on the test contactor. After the electrical test, there may
be a visual test in which an outward appearance of the IC devices
such as a shape, color, surface roughness and the like are tested.
The DUTs are then proceeded to the sorting process based on the
test results.
A control and power source 34 works as a system controller to
control the operation of the test handler 9 as well as provide
power to the test handler 9. A TV monitor 35 is to monitor the
positioning between the DUT and the test contactor. By opening the
cover with the handle 36, the surface of the test handler as shown
in the plan view of FIG. 5 will be disclosed.
As shown in the foregoing example, the conventional test handler is
integrally formed of the test area, the loader and unloader, and
the sorting area. The IC tester and the automatic test handler are
fixed together and installed in a special test room in, for
example, a semiconductor production plant. The test room is a clean
room in which temperature, humidity and dust of air are controlled
in a degree higher than the ordinary factory. Since the recent
semiconductor devices are complicated, miniaturized and high speed,
such a clean room is necessary to fully evaluate the devices.
As a consequence, the cost per square meter of the test room is
significantly higher than the other facilities in the semiconductor
production plant. Because the floor space cost of the test room is
high, the overall test cost of the IC devices becomes high. Thus,
there is a need to effectively use the surface area of the test
room to decrease the test cost of the IC devices.
The IC tester has been reduced in size by using high density
electronics parts and by incorporating an improved electrical and
mechanical design. However, since most of the functional blocks in
the horizontal transfer type test handler are formed of mechanical
parts, it is difficult to decrease the overall size of the test
handler. For example, the size of the automatic test handler of
FIGS. 5 and 6 is 180 cm by 106 cm in plan view, which is considered
to be large relative to the size of the IC tester. Thus, the size
of the automatic test handler tends to limit the reduction of the
overall test cost, since it occupies a relatively large area of the
test room.
Further, the time required for testing the DUTs in the test area
and the time required for sorting the DUTs are usually different.
For example, the testing time may be longer than the sorting time
for specific kinds of DUTs or specific type of test. In other
instances, the testing time may be shorter than the sorting time.
In either case, the overall time required for the automatic test
handler to evaluate the IC devices is determined by the slowest
step. Thus, for example, even if an automatic test handler has an
ability of high speed testing, the overall test efficiency is
limited by the low speed of sorting.
Japanese Patent Publication No. 6-95125 discloses a structure of an
automatic test handler in which a test area and a sorting area are
mechanically separated. This technology includes an information
storage which is attached to each tray cassette, an information
write-in device for writing the position (coordinates) and the test
results of each DUT in a tray in the information storage which is
attached to the tray cassette, and an information read-out device
for reading the data stored in the information storage attached to
the tray cassette.
In this conventional example, the information for the DUTs is
provided for every tray cassette. Thus, IC trays in the tray
cassette are not identifiable from one another, which requires that
the IC trays have to be strictly united to the tray cassette. In
case where the order of the IC tray in the tray cassette has
accidentally changed, the information regarding the DUTs becomes
useless. Further, since all the test information of the DUTs in the
tray cassette are stored in the information storage provided to the
tray cassette, the volume of the information to be stored is
limited by the capacity of the storage. Thus, there is a
disadvantage in which the detailed test data, such as designations
of the IC tester, test area and test sockets and the like are not
available through the information storage.
SUMMARY OF THE INVENTION
It is therefore, an object of the present invention to provide an
automatic test handler system in which a test machine and a sorting
machine are separated so that only the testing machine is installed
in a clean room while the testing machine and the sorting machine
are connected by a data communication network.
It is another object of the present invention to provide an
automatic test handler system which is capable of decreasing the
needed surface area in a clean room occupied by the handler system
so as to reduce the test cost of IC devices because the floor space
cost of the clean room is high.
It is a further object of the present invention to provide an
automatic test handler system which is capable of increasing the
number of IC devices to be tested in a unit space of a clean room
which requires a high space cost thereby improving the test
efficiency.
It is a further object of the present invention to provide an
automatic test handler system which is capable of optimizing the
abilities of a testing machine and a sorting machine so as to
maximize an overall test performance of the test handler system and
an IC tester.
It is a further object of the present invention to provide an
automatic test handler system which is capable of separately
providing identification information on every IC tray and tray
cassette.
To achieve these objectives, the test handler of the present
invention has a structure in which a test area and a sorting area
are mechanically separated so that the test area is installed in
the clean room while the sorting area is positioned outside of the
clean room. Each IC tray is provided with a data card showing
identification data of the IC tray. The IC trays are installed in a
tray cassette which is also provided with a data card indicating
tray cassette identification data.
The test handler of the present invention includes:
a testing machine for testing the IC devices by contacting the IC
devices with test contactors whereby providing test signals from
the IC tester to the IC devices and receiving resulted signals from
the IC devices, wherein the testing machine is installed in a test
room in which dust, temperature and humidity are controlled in a
high degree,
a sorting machine installed outside of the test room for sorting
the IC devices that have been tested based on the test results
wherein the sorting machine has a plurality of sort stations for
receiving the IC devices based on categories defined in the test
results,
a tray cassette for installing the plurality of IC trays containing
the IC devices wherein the tray cassette is provided with a tray
cassette identification number,
each of the IC tray is provided with an IC tray identification
number and is horizontally transferred on the testing machine and
the sorting machine, and
a data communication network connected between the testing machine
and the sorting machine for transmitting data showing the test
results and position information of each of the IC devices in the
IC trays.
According to the automatic test handler system of the present
invention, the testing machine and the sorting machine are
mechanically separated from one another so that only the testing
machine is installed in the test room while the testing machine and
the sorting machine are electrically connected by the data
communication network. Therefore, the automatic test handler system
of the present invention is capable of decreasing a necessary
surface area in the test room, which is a clean room whose space
cost is very high, resulting in the reduction of the overall test
cost of the IC devices.
In other words, for the same surface area of the test room, more
testing machines can be installed. Thus, the automatic test handler
system of the present invention is capable of increasing the number
of IC devices to be tested in the clean room thereby improving the
test efficiency and decreasing the test cost. Furthermore, the
automatic test handler system of the present invention is capable
of optimizing the abilities of the testing machine and the sorting
machine so as to maximize an overall test performance of the test
handler system and an IC tester.
The automatic test handler system includes a plurality of IC trays
each of which carries a large number of IC devices. The IC trays
are installed in the tray cassette which is transferred between the
testing machine and the sorting machine. In the present invention,
identification information is provided on each IC tray and on the
tray cassette so that the identification information is read by an
external data reader. Thus, even if the order of the IC trays is
accidentally mixed-up failed, the testing operation or sorting
operation of the IC devices on the IC tray can be continued without
an error.
The test results and other information are transmitted through the
data communication network which is governed by the host computer
or the computer in the testing machine, there is no limitation of
data capacity which will be found in the conventional
technology.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic diagram showing a plan view of one of the
examples of the automatic test handler system of the present
invention in which two sets of IC tester and test handler system
are included.
FIG. 2 is a schematic view showing a plan view of the testing
machine in the automatic test handler system of the present
invention of FIG. 1.
FIG. 3 is a schematic view showing a plan view of the sorting
machine in the automatic test handler system of the present
invention of FIG. 1.
FIG. 4A is a perspective view showing an example of IC tray
cassette in the present invention and FIG. 4B is a perspective view
showing an example of IC tray in the present invention.
FIG. 5 is a plan view showing an example of structure in the
conventional test handler used in combination with an IC
tester.
FIG. 6 is a perspective view of the conventional test handler of
FIG. 5.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The preferred embodiment of the present invention will be described
with reference to the drawings. FIG. 1 is a schematic diagram
showing a plan view of an embodiment of the automatic test handler
system of the present invention. In the example of FIG. 1, there is
shown two sets of IC tester and test handler.
In the present invention, the test handler system has a structure
in which a testing machine and a sorting machine are mechanically
separated so that the testing machine is installed in a clean room
(test room) while the sorting machine is positioned outside of the
clean room. Each IC tray is provided with a data storage or data
card to store data indicating an identification number of the IC
tray. The IC trays are installed in a tray cassette which is also
provided with a data card to store data indicating an
identification number of the tray cassette.
Since the sorting machine is separated from the testing machine,
the testing machine needs a smaller surface area of the clean room.
For example, the testing machine has a size of 120 cm by 90 cm
which is about a half of the conventional test handler. Thus, as in
the example of FIG. 1, two testing machines may be connected to one
IC tester in the same floor space that would be assigned to only
one test handler of the conventional technology.
In FIG. 1, two IC testers 5 are provided in a test center 50,
typically a clean room, for testing IC devices. Each IC tester 5
has two test heads 6 each of which is connected to a corresponding
testing machine 1 of the handler system. As noted above, the two
testing machines 1 occupy a space equivalent to one conventional
test handler since the size of the testing machine is about 50%
smaller than the conventional test handler.
Sorting machines 2 are provided in a sort center which is typically
in a semiconductor plant but outside of the clean room. With
reference to FIGS. 4A and 4B, IC devices to be tested by the IC
testers 5 and the testing machines 1 are aligned on IC trays 7. The
IC trays 7 are installed in tray cassettes 3 which are transferred
to the sorting machines 2 by a robot carrier or a belt conveyer and
the like. The IC testers 5, the testing machines 1 and the sorting
machines are connected through a data communication network 53
which is controlled by a data communication controller 54. Further,
to establish operational control of the overall test system, the IC
testers 5 and the sorting machines 2 are connected to a host
computer 52.
FIG. 2 shows a plan view of the testing machine 1 in the automatic
test handler system of FIG. 1. In FIG. 2, the testing machine 1
includes a movable arm 12 which is movably mounted on a rail
11.sub.1 at its one end. The other end of the movable arm 12 may be
slidably guided in a guide groove (not shown) on the surface of the
testing machine. A movable arm 28 is mounted on a rail 11.sub.2 at
its one end. The other end of the movable arm 28 may be slidably
guided in a guide groove (not shown) on the surface of the testing
machine. The movable arms 12 and 28 move on the rails 11.sub.1 and
11.sub.2, respectively, in the X direction on the surface of the
testing machine 1.
On the movable arm 12, there is provided a movable carrier 13 which
moves along the movable arm 12 in the Y direction on the surface of
the testing machine 1. Similarly, on the movable arm 28, there is
provided a movable carrier 29 which moves along the movable arm 28
in the Y direction on the surface of the testing machine 1. Thus,
the movable carriers 13 and 29 can take any positions on the
surface, i.e., the X-Y plane of the testing machine 1 within the
area determined by the rails 11.sub.1 and 11.sub.2 and the movable
arms 12 and 28. In the movable area of the carrier 13, a loader 14
and an empty tray area 26 are provided as well as a heater area 15
and a buffer 16. In the movable area of the carrier 29, an unloader
23 and a buffer 22 are provided.
A movable carrier 19 is mounted on a rail 20 which is oriented in
the Y direction. The movable carrier 19 moves on the rail 20 in the
Y direction on the surface of the testing machine 1. The test head
6 of the IC tester 5 is positioned under the testing machine 1 such
that a test area 33 of the testing machine contacts with the test
head 6. The test area 33 includes test contactors 21 which receive
the IC devices to be tested. Preferably, the rail 20 is so
positioned that its center comes right above the test contactors
21. The buffers 16 and 22 move in the X direction from the
positions in the moving areas of the movable carriers 12 and 29 to
the positions under the rail 20 as shown by the dotted lines in
FIG. 2.
The testing machine starts testing IC devices after being provided
with the tray cassettes 3 in the loader 14 of the testing machine
1. The tray cassette 3 includes several ten IC trays 7 each of
which carries a large number of IC devices to be tested. Each of
the tray cassette 3 and the IC trays 7 has a data card at its
outside to be readable by an external data reader. The data card
includes an identification number of the corresponding tray
cassette or the IC tray. The identification number may be
expressed, typically by a bar code to be easily read by an
opto-electronic reader. However, other types of data card or means
to express identity, such as using a magnetic material, an optical
device or mechanical holes or grooves can also be applicable to the
present invention.
The DUTs 10 in the uppermost IC tray 7 are taken out, one by one,
or two or more at a time, by the movable carrier 13. The DUTs 10
are placed on the heater area 15, if necessary, to receive the heat
for raising the inner temperature of the DUTs to a predetermined
level. The testing machine may also include a cooler to undertake a
low temperature test. The IC trays 7 which are now empty are
transferred to the unloader 23 to receive the DUTs that have been
tested.
The DUTs 10 heated by the heater 15 are then placed on the buffer
16 which moves in the X direction to a dotted line position right
under the rail 20 in the test area 33. In the test area 13, the
movable carrier 19 picks the DUT 10 on the buffer 16 and places the
DUT on the test contactor 21. Although not shown, test signals from
the IC tester are provided to the test contactor 21 through the
test head 6 and applied to the DUT 10. The resulting output signals
from the DUT 10 are transmitted to the IC tester through the test
contactor 21 and the test head 6 to be evaluated by the IC tester 5
by being compared with expected data generated by the IC tester
5.
After the test, the DUT 10 is picked from the test contactor 21 by
the movable carrier 19 and placed on the buffer 22 which is
positioned right under the rail 20 in the test area 33 as shown in
the dotted line. The buffer 22 returns to the original position so
that the movable carrier 29 will take the tested DUTs and transfer
them to the unloader 23. In the unloader 23, the tested DUTs are
placed on the IC trays 7. The IC trays 7 having the tested DUTs are
stocked in the tray cassette 3 (FIG. 4A).
Various test data including a position of each DUT in the IC tray
7, test categories and fail categories of the DUTs, identification
numbers of the IC trays 7, and identification numbers of the tray
cassette 3 is stored in the host computer 52 of FIG. 1 or computers
(not shown) in the testing machines 1. The test data is transferred
to the sorting machine 2 through the data communication network 53
to proceed sorting operations in the sorting machine 2.
FIG. 3 shows a plan view of the sorting machine in the automatic
test handler system of the present invention. As noted above, the
sorting machine 2 will be installed in the area other than the
expensive clean room. Thus, the spacing for the sorting machine is
not a big concern in decreasing the test cost of the IC devices. As
a consequence, the sorting machine 2 may include many sort stations
so that the tested IC devices can be classified into various test
categories and fail categories. The numbers of the sort stations
may be determined by taking the speeds of the testing machine 1 and
the sorting machine 2 into account to maximize the overall test
efficiency.
The sorting machine in FIG. 3 includes a loader 40, an empty tray
station 41, sort stations 42-46, a rail 47, a movable arm 48 and a
movable carrier 49. The rail 47 extends in an area proximate to the
loader 40, the empty tray station 41 and all of the sort stations
42-46. The movable arm 48 moves along the rail 47 on the surface of
the sorting machine 2. The movable carrier 49 moves along the
movable arm 48 which is perpendicular to the rail 47. Thus, the
movable carrier 49 can take any positions on the surface, i.e., the
X-Y plane of the sorting machine 2 under which the loader 40, the
empty tray station 41 and all of the sort stations 42-46 are
provided.
In this arrangement, the sorting operation starts when the tray
cassette 3 having the IC trays filled with the tested DUTs is
inserted in the loader 40. The data showing the test results are
transmitted from the host computer 52 or the computers in the
testing machines 1 through the data communication network 53 to the
sorting machine 2. Thus, the sorting operation is performed based
on the data from the communication network 53.
Prior to actually classifying the tested DUTs, the identification
numbers of the IC trays 7 and the tray cassette 3 are read by the
data reader (not shown) in the sorting machine. Such identification
numbers are confirmed based on the data from the testing machine 1
through the data communication network 53. Then the DUTs are
distributed to the corresponding sort stations 42-46 based on the
test results and the position data provided through the data
communication network 53 for each DUT in the IC tray 7.
Because the sorting machine of the present invention can include
more sort stations than the conventional technology, the sorting
operation with higher flexibility is available such as larger
numbers of classification categories. Further, an optimum overall
testing speed may be available by adjusting the number of sort
stations when there is a difference between the testing speed in
the testing machine 1 and the sorting speed in the sorting machine
2.
FIG. 4A is a perspective view showing an example of the IC tray
cassette 3 in the present invention and FIG. 4B is a perspective
view showing an example of the IC tray 7 in the present invention.
The tray cassette 3 has an identification (ID) number 8.sub.2 and
the IC tray 7 has an identification (ID) number 8.sub.1 to be
readable from their outside surfaces by an external data reader.
Preferably, the ID number 8.sub.2 on the tray cassette 3 is
automatically read by the testing machine 1 or the sorting machine
2 when the tray cassette is inserted in the loader 14 (testing
machine) or the loader 40 (sorting machine), respectively.
As noted above, the IC trays 7 having IC devices to be tested are
installed in the tray cassette 3 which is loaded in the testing
machine 1. During the test, the tray cassette 3 receives the IC
trays 7 having IC devices that have been tested. After the test,
the tray cassette 3 is transferred to the sorting machine 2 wherein
the tested IC devices are sorted according to the test results
provided through the network 53. The ID number 8.sub.1 of the IC
tray 7 is read by the testing machine 1 or the sorting machine 2
when the IC tray 7 comes to the uppermost position in the cassette
tray 3 at the loaders 14 and 40.
As has been described, according to the automatic test handler
system of the present invention, a testing machine and a sorting
machine are mechanically separated from one another so that only
the testing machine is installed in a test room while the testing
machine and the sorting machine are electrically connected by a
data communication network. Therefore, the automatic test handler
system of the present invention is capable of decreasing a
necessary surface area in the test room, which is a clean room
whose space cost is very high, so as to reduce the overall test
cost of the IC devices.
In other words, for the same surface area of the test room, more
testing machines can be installed. Thus, the automatic test handler
system of the present invention is capable of increasing the number
of IC devices to be tested in the clean room thereby improving the
test efficiency and decreasing the test cost. Furthermore, the
automatic test handler system of the present invention is capable
of optimizing the abilities of the testing machine and the sorting
machine so as to maximize an overall test performance of the test
handler system and an IC tester.
The automatic test handler system includes a plurality of IC trays
each of which carries a large number of IC devices. The IC trays
are installed in the tray cassette which is transferred between the
testing machine and the sorting machine. In the present invention,
identification information is provided on each IC tray and on the
tray cassette so that the identification information is read by an
external data reader. Thus, even if the order of the IC trays is
accidentally mixed-up, the testing operation or sorting operation
of the IC devices on the IC tray can be continued without an
error.
The test results and other information are transmitted through the
data communication network which is governed by the host computer
or the computer in the testing machine, there is no limitation of
data capacity which will be found in the conventional
technology.
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